In an extension to the internal model based approach, our paper got accepted at ICRA 2015 to present how the stance movement is controlled and (in addition) how an evading reflex can be incorporated into the overall control architecture:
a concept that allows the inherently compliant hexapod robot HECTOR to walk on uneven terrain and to overcome moderate obstacles by means of a decentralized walking controller. An important prerequisite is the availability of inherently compliant joint drives with an increased power/weight-ratio.
Citation: Paskarbeit, J., Schilling, M., Schmitz, J., and Schneider, A. (2015), “Obstacle crossing of a real, compliant robot based on local evasion movements and averaging of stance heights using singular value decomposition,” in IEEE International Conference on Robotics and Automation (ICRA), pp.3140-3145.